Anyone thinking of doing the coil relay modification...DO IT!!!!

[81GS1000L]

Hi All....
All I can say is wow...unreal...unbelievable...incredible...awesome...speechless...etc, etc.
Really, can't say enough for the effects this modification has done for my bike.
I have done the r/r changeover which was a big improvement!
But this, this was awesome. Before, my bike was a capitol "B" to start when cold. It would turn over forever and just not catch unless I held my tongue just right...thought maybe it was carb, fuel, but gut instinct said spark. Went through all the very helpful checklists and info from here and Bikecliff's website. Learned how to tune up my spark plug wires which I am sure also helped as I found I had 1 bad cap, and the other three above the suggested ohms. Switched those out and while I was at it, went ahead with the coil relay modification. Easy enough to do...put the tank back on. Hit the start button and it fired instantly. I mean hardly a turn over and it fired and stayed at a nice idle. Put the choke in and took her for a ride. I would normally be only so lucky to get it too start , especially because the battery would die and then I would give up, take the battery out, recharge it, and try again the next day. Don't get me wrong...it would start once in a while, but not reliably when i wanted to actually go for a ride...so it really sucked. Have read about the "some say it is the best mod you can do for an older bike"...and wow. So in short, I truthfully can't say it was the spark plug caps, which i know helped, or the relay...but I don't give a hoot. The bike starts like it should. You can tell I am just babbling at this point...but the whole point is to say thanks again to all the people here with a tonne of knowledge and that are so eager to share. And also, if any of the above symptoms seem similar to yours...do this mod!
Enough already...
Rick

 

[crapwacker]

What did you use for your relay?

 

[rustybronco]

Learned how to tune up my spark plug wires which I am sure also helped as I found I had 1 bad cap, and the other three above the suggested ohms.

So in short, I truthfully can't say it was the spark plug caps, which i know helped, or the relay...but I don't give a hoot. The bike starts like it should.

What was the final value that you measured on the other three plug caps? just gathering information, so that it may help others with the same issues.

Thanks in advance.
Dale

 

[Steve]

You think it starts easily now? :-k

Wait until you adjust the valves, too.

I have not done the coil relay mod on any of my bikes, but simply cleaning the carbs and adjusting the valves has done wonders.
They start so easily now, I have a feeling that if I do the coil relay, too, the bike might just start itself as I approach it.

.

 

[Addy Leung]

Hi All, I also did this relay Mod to my 81-GS1100(16v) with dyna S and green coils and it is also getting 200% good result.

BUT, I do want to tell there is some draw back in this relay mod design that you need to know.That is why the manufacturer did not apply this design in the bike when they built it in the factory.

Just think if you are riding the bike on highway and the relay is out of order suddenly( I can tell it is frequent happen and easy to happen) and the contact is opened, the bike will lose all the power. No one know what will happen with theose big cars follow you.
There is a lot of reason cause the relay out of order: charging voltage too high, vibration too much, aged relay.
Also, if the relay contact is melted together for some reasons and it can not be released to open the contact. Then the bike may not be able to switch off even you turn the key off and pushed the right hand control emergency switch off.

So when you chose a relay for this mod, you better chose a one is real good one design for 10-16V DC range and it is vibration proof.
I found one relay on www.RSWWW.com with parts no. 235-5469, and now I also use it now after a cheap relay was out of order.

It is the spec of it

http://docs-europe.electrocomponents.com/webdocs/008b/0900766b8008b10d.pdf

Hope it will help to ride in safe.

 

[posplayr]

Hi All, I also did this relay Mod to my 81-GS1100(16v) with dyna S and green coils and it is also getting 200% good result.

BUT, I do want to tell there is some draw back in this relay mod design that you need to know.That is why the manufacturer did not apply this design in the bike when they built it in the factory.

Just think if you are riding the bike on highway and the relay is out of order suddenly( I can tell it is frequent happen and easy to happen) and the contact is opened, the bike will lose all the power. No one know what will happen with theose big cars follow you.
There is a lot of reason cause the relay out of order: charging voltage too high, vibration too much, aged relay.
Also, if the relay contact is melted together for some reasons and it can not be released to open the contact. Then the bike may not be able to switch off even you turn the key off and pushed the right hand control emergency switch off.

So when you chose a relay for this mod, you better chose a one is real good one design for 10-16V DC range and it is vibration proof.
I found one relay on www.RSWWW.com with parts no. 235-5469, and now I also use it now after a cheap relay was out of order.

It is the spec of it

http://docs-europe.electrocomponents.com/webdocs/008b/0900766b8008b10d.pdf

Hope it will help to ride in safe.

Andy,
You are dead on correct; I might add though that the location/mounting of the relay will have much to do with it's longevity. Mine is mounted in rubber off the battery box which is also mounted in rubber. This provides a double level of mechanical isolation between engine and relay as well as getting the relay away from the engine heat.
I recently had what I thought was a relay failure; it turned out it as a blown 10 amp fuse on the ignition circuit. A easily accessible switch to circumvent the relay would have gotten me safely to the side of the road; I was on a busy freeway and just happened to luck out.

http://www.thegsresources.com/_forum/showthread.php?t=141055

For anybody in the US these Tyco Relays (formerly Bosch) are apparently environmentally sealed and really are only marginally more expensive.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=330-070

Pos

 

[sschering]

The relay I plan to use is a ford fuel pump relay..
They are easy to find on any fox body ford, already designed for life in an engine compartment, have a nice secure connector (if the wrecking yard doesn't mind a little harness hacking) and come with rubber isolator mount.
If you burn one up almost any autozone should stock a spare for $12..
Pack a spare under the seat no matter what one you use.

 

[Richsuz]

SO, my bike always gave me problems starting in the morning. Full choke, it toke a few tries. Started really slow, and even with the full choke, it would pot pot under 500rpm. Checked the voltage at the coils and was 12.2 v. So I did not see a reason to do the coil mod. I have not done the carbs, I imagine there is something not right with the cold start circuit, and also I need to do a valve job, but....
Well, I went ahead and did the coil mod two days ago. The voltage at the coils is the same, but for some reason the bike now starts at first try. AMAZING!. One thing is also different. Voltage at the battery is 12.2 V even at 4K rpm. It used to get to 13.4. Did I do anything wrong? All I did was short the orange/white wiress to the switch and connected it to the relay. then I daisy chained the coils to the relay. The other two ends of the relay to the battery, the positive side via a 10 amp fuse. I purchased a 40 amp relay from the bosch dealer, but its not labeled BOSCH. I will be carrying a spare, just in case. How long should I expect this relay to work before failure? Should it be replaced on a scheduled basis?

 

[spyug]

Richsuz you haven'tdone anything wrong but your charging circuit isn't working up to par. You should be shooting into the 14v at those revs.

Read over the stator papers and the fault finding flow chart but also start by cleaning and or replacing all contacts from the stator to the R/R and to the fuse block. Also run an additional ground line from the R/r ( the Black/white wire) directly to the negative battery terminal.

Doing the cleanup will likely fix things but you may have a duff R/r. They are not the strongest devicer and many folks chnge them out for one from a Honda. Our pal Duaneage is the go to guy for these.

Tidy up this problem before it leaves you stranded somewhere.

Good luck with it and let us know how you make out.
Spyug

 

[tkent02]

SO, my bike always gave me problems starting in the morning. Full choke, it toke a few tries. Started really slow, and even with the full choke, it would pot pot under 500rpm. Checked the voltage at the coils and was 12.2 v. So I did not see a reason to do the coil mod. I have not done the carbs, I imagine there is something not right with the cold start circuit, and also I need to do a valve job, but....
Well, I went ahead and did the coil mod two days ago. The voltage at the coils is the same, but for some reason the bike now starts at first try. AMAZING!. One thing is also different. Voltage at the battery is 12.2 V even at 4K rpm. It used to get to 13.4. Did I do anything wrong? All I did was short the orange/white wiress to the switch and connected it to the relay. then I daisy chained the coils to the relay. The other two ends of the relay to the battery, the positive side via a 10 amp fuse. I purchased a 40 amp relay from the bosch dealer, but its not labeled BOSCH. I will be carrying a spare, just in case. How long should I expect this relay to work before failure? Should it be replaced on a scheduled basis?

I've never had a Bosch relay fail. Anywhere.